The present invention relates to a double-sided cutting insert for chipforming machining comprising a body of generally polygonal shape having essentially identical upper and lower rake faces, and side faces intersecting the upper and lower rake faces to form cutting edges, pairs of the side faces intersecting each other to form cutting corners. Each of the upper and lower rake faces is provided with a central recess.
A double-sided cutting insert for chipforming machining is disclosed in U.S. Pat. No. 4,312,250 in which each upper and lower rake face of the insert has a centrally raised portion lying in uppermost and lowermost planes of the insert for the purpose of functioning as a support surface when resting upon a mounting surface of a holder. The cutting edge and its adjacent chip face are spaced from the mounting surface of the holder and are unsupported therebelow whereby the insert is susceptible to failure when subjected to large tensile forces.
It is an object of the present invention to provide a double-sided cutting insert which exhibits maximum strength during machining.
It is another object of the present invention to provide such a cutting insert which has a plurality of cutting edges.